The thesis analyzes the Spanish ministerial elite through the political and social origins and the political and ministerial careers of the executive members from Adolfo Suárez up to Jose Luis Rodríguez Zapatero's first office (cabinet), between July 1976 and April 2004. The research goes on the analytical frame for the ministers, which has been applied for other Europe's countries by Jean Blondel and his colleagues. The interest of this research is related to the factors explaining the success of the politicians who accede to the maximum executive post, following the principal questions established by the previous studies of political elites.During the analyzed period, there have taken place three big changes of social and institutional type, which have influenced the selection of the ministerial elite: the modernization of the Spanish society, the democratization of the political institutions, by means of the establishment of a parliamentary system and of a party democracy, and the impulse of a process of decentralization that has given place to the appearance of new political arenas. In the frame of these changes, the ministerial elite has experienced also the influence of other factors tied to the political dynamics: the electoral evolution, the formation of coalitions to reach parliamentary majorities and the succession of ministerial reshuffles.To explain the impact of these factors on the process of ministerial selection, three main hypotheses are proposed. First, the social change in the profile of the ministers as a result of the modernization of the Spanish society. Second, the impulse of the parliamentary and party careers of the new ministers, as well as of the territorial careers in different arenas, as result of the impact of the new institutional configuration. Finally, the differentiation set in the ministerial careers, as result of the influence of the different models of political paths on the later itinerary that the ministers realize inside executive. This differentiation leads to different types of ministers and departments, according to the physiognomy of the ministerial career. This object -the ministerial career- is defined by three dimensions: time (duration and age of access), position (types of department and sequence of access) and itinerary (continuity and mobility). The conclusions of the thesis tint the content of our hypotheses and help to identify different ministers' and departments' typologies that have taken place during the democratic period in Spain.